IPv4 Documentation

Operator-level documentation for teams that plan, route, and account for IPv4 address space. Written for network engineers rather than newcomers: every page assumes you know what a prefix is and gets to the practical part quickly.

Start here

Subnet calculator

Split a prefix, check host counts, and share the result as a link.

CIDR chart

Every prefix length from /0 to /32 with masks and host counts.

IPAM

Plan and track address space without spreadsheets.

By task

Planning address space. Start with address plan design, then pick a tool in the IPAM tools reference. If you run leased space alongside your own, see IPAM for leased space.

Preparing a block for production. Check reserved and bogon ranges before you announce, confirm registry records with WHOIS and RDAP, and make sure your utilization records will survive an RIR audit.

Getting an ASN. The ASN registration walkthrough covers requirements and paperwork for each registry.